Detect externalModule dependencies inside subflow modules

Not sure this is 100% the right approach. If a subflow module has a dependency
it should be in the subflow's package.json and therefore installed next to the
subflow module in ~/.node-red/node_modules.

By treating it as a 'normal' external module, it will be dynamically installed
in ~/.node-red/externalModules. That then exposes the module to the user
who won't know why its there and may remove it.

It would be better to allow nodes inside a subflow module to require
from ~/.node-red/node_modules and not limit it to the externalModules
dir. The hard part is knowing when to do that.

packages/node_modules/@node-red/registry/lib/externalModules.js

@@ -6,6 +6,7 @@
 const fs = require("fs-extra");
 const registryUtil = require("./util");
 const path = require("path");
+const clone = require("clone");
 const exec = require("@node-red/util").exec;
 const log = require("@node-red/util").log;
 
@@ -16,6 +17,7 @@ const EXTERNAL_MODULES_DIR = "externalModules";
 const NPM_COMMAND = (process.platform === "win32") ? "npm.cmd" : "npm";
 
 let registeredTypes = {};
+let subflowTypes = {};
 let settings;
 
 let knownExternalModules = {};
@@ -58,6 +60,10 @@ function register(type, dynamicModuleListProperty) {
     registeredTypes[type] = dynamicModuleListProperty;
 }
 
+function registerSubflow(type, subflowConfig) {
+    subflowTypes[type] = subflowConfig;
+}
+
 function requireModule(module) {
     if (!registryUtil.checkModuleAllowed( module, null,installAllowList,installDenyList)) {
         const e = new Error("Module not allowed");
@@ -95,15 +101,21 @@ function isInstalled(moduleDetails) {
     return moduleDetails.builtin || moduleDetails.known;
 }
 
+
 async function checkFlowDependencies(flowConfig) {
+    let nodes = clone(flowConfig);
     await refreshExternalModules();
 
     const checkedModules = {};
     const promises = [];
     const errors = [];
-
-    flowConfig.forEach(n => {
-        if (registeredTypes[n.type]) {
+    const checkedSubflows = {};
+    while (nodes.length > 0) {
+        let n = nodes.shift();
+        if (subflowTypes[n.type] && !checkedSubflows[n.type]) {
+            checkedSubflows[n.type] = true;
+            nodes = nodes.concat(subflowTypes[n.type].flow)
+        } else if (registeredTypes[n.type]) {
             let nodeModules = n[registeredTypes[n.type]] || [];
             if (!Array.isArray(nodeModules)) {
                 nodeModules = [nodeModules]
@@ -135,8 +147,7 @@ async function checkFlowDependencies(flowConfig) {
                 }
             })
         }
-    })
-
+    }
     return Promise.all(promises).then(refreshExternalModules).then(() => {
         if (errors.length > 0) {
             throw errors;
@@ -205,6 +216,7 @@ async function installModule(moduleDetails) {
 module.exports = {
     init: init,
     register: register,
+    registerSubflow: registerSubflow,
     checkFlowDependencies: checkFlowDependencies,
     require: requireModule
 }

packages/node_modules/@node-red/registry/lib/registry.js

@@ -456,6 +456,9 @@ function registerSubflow(nodeSet, subflow) {
         nodeSetInfo.config = result.config;
     }
     subflowModules[result.type] = result;
+    externalModules.registerSubflow(result.type,subflow);
+
+
     events.emit("type-registered",result.type);
     return result;
 }

test/resources/subflow/package/package.json

@@ -1,6 +1,6 @@
 {
   "name": "test-subflow-mod",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description": "",
   "keywords": [],
   "license": "ISC",
@@ -13,6 +13,7 @@
       ]
   },
   "dependencies": {
-      "node-red-node-random": "*"
+      "node-red-node-random": "*",
+      "cowsay2": "*"
   }
 }

test/resources/subflow/package/subflow.json

@@ -189,6 +189,7 @@
             "noerr": 0,
             "initialize": "",
             "finalize": "",
+            "libs": [ {"var":"cowsay2","module":"cowsay2"}],
             "x": 240,
             "y": 100,
             "wires": [